#3 Ander Herrera
Another signing of the Louis Van Gaal era, Herrera is still unsure of his own position in the side. Starting off as a deep lying midfielder, he has been utilized in the box-to-box and ball winning midfielder roles as well.
Mourinho has even played the Spaniard in defense, but Herrera simply isn't playing at the level demanded by a top side like United. Woodward needs to sell the former Athletic Bilbao man while he still possesses a decent market value.
#4 Antonio Valencia
Antonio Valencia has been a great servant to United over the years. The Ecuadorian began his United career as a winger but has since been converted into a right-back.
Similar to Darmian though, while Valencia is a safe option in defense, he simply isn't dynamic enough to be a Premier League full-back. His age has also been showing over the last season; the 33-year-old no longer has the legs to play at the top level of English football.
United are unlikely to gain a large sum through his sale, but a fee of 2-3 million can be useful. His departure would provide the opportunity that youngsters like Diogo Dalot deserve.